Whereas the years from 1962 to 1967 were devoted to building the communications
foundation in Vietnam, 1968 and 1969 were years of completion and sophistication.
During that period the huge Integrated Wideband Communications System was finished.
The telephone and message networks in Vietnam were further integrated and consolidated.
For the first time, modern automatic switching equipment for both voice and
message traffic was introduced into a combat zone.

Completion of the Integrated Communications
System

The final links of Phases I and II of the Integrated Wideband Communications
System were completed in the first two months of 1968. Their completion marked
a communications milestone, extending high quality, multichannel communications
throughout Vietnam: north to Hue, south to major cities in the Mekong Delta,
and westward into Thailand. The fact that these two phases of the wideband system
were completed and cut to traffic at this time had extreme combat significance.
Many critical mobile assets could now be relieved from their interim service
in the long-lines system and could be transferred to the north in support of
the heavy troop buildup and unit relocations within I Corps Tactical Zone. The
Tet offensive and the massing of enemy troops in the Demilitarized Zone
and in the area of the Khe Sanh combat base had led to the strengthening of
I Corps Tactical Zone.

Construction and installation at the new sites of Phase III, the final phase
of the integrated long-lines system, were underway at the outset of 1968 and
continued through the perilous weeks of the Tet offensive. Work on the
new Phase III links and on system improvements progressed steadily, and by the
end of the year all but one of the twenty-six links and upgrades had been completed
and put into service. The uncompleted link was between Qui Nhon and Nha Trang.

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This last link of Phase III was accepted and put to traffic in January 1969.
After four and a half years of effort and at a cost of approximately $235 million,
the most massive undertaking in the history of the Army Signal Corps was finally
finished, constituting throughout South Vietnam and Thailand the fixed-station,
commercial-quality Integrated Wideband Communications System. (Map 7)

One final addition to the civilian contract for the wideband system was awarded
in March 1968 for the provision and installation of four transportable, line-of-sight,
microwave terminals. These transportable facilities had all the technical control
capabilities and high channel capacity of the fixed wideband stations, plus
the very distinct advantage that they could be moved if needed elsewhere. The
first of these microwave terminals to be put into full operation was at Dong
Ha, just a few kilometers south of the Demilitarized Zone. On 20 April 1969
this terminal linked with the fixed-station terminal at Quang Tri. Work was
continuing, mean­while, on the three other transportable facilities being installed
at Di An, a few miles north of Saigon, at Sa Dec, in the delta, and at Dong
Ba Thin, near Cam Ranh Bay. All these facilities were operational by July 1969.

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MAP 7

Integration of Defense Communications

In November 1968, the Department of Defense redesignated its telecommunications
systems in Southeast Asia as the Integrated

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Communications System, Southeast Asia. This move involved more than just another
complicated name. Now one single system incorporated previously distinct elements:
the large fixed-station wideband system, the undersea cable system that looped
around the coast of Vietnam to Thailand, and a considerable number of mobile line-of-sight
and tropospheric scatter radio facilities, supplementing and extending the terminal
points, or tails, of the Defense Communications System in Vietnam.

Soon after the completion of the fixed wideband system and the establishment
of the over-all integrated system, numerous transportable combat communications
links were released, and, since they were no longer needed to support the long-lines
network, they were at once relocated to provide support for combat operations.
A most critical and immediate need was the major reconfiguration of the communications
in I Corps Tactical Zone. Reconfiguration was completed in early January 1969,
thereby releasing U.S. Air Force tropospheric scatter systems, which had been
"temporarily" deployed to Vietnam in 1966 when it was apparent that
the rapid influx of troops was surpassing the limited capability of the long-linessystem. The Air Force equipment, however, had remained in place and in use
for three years, until the back­bone system attained full capacity in 1969.

Similar "purging" of the integrated long-lines system was soon accomplished
throughout the rest of Vietnam; the result was the release of considerable quantities
of mobile signal equipment that had been previously committed, as an interim
stopgap measure, to the support of the Defense Communications System. The Integrated
Communications System, Southeast Asia, became stable in mid-1969, thus yielding
the fruit of much labor.

Automatic Message Switching-Another First

The activation of automatic message and data switching centers at Phu Lam
and Nha Trang in early 1968 introduced the world­wide Automatic Digital Network
into Vietnam. The Phu Lam switching center of this network began passing traffic
in March 1968. The flow of traffic through the Phu Lam switching center wrote
a new chapter in communications history: the multimillion dollar switch was
the first of its kind ever to be installed in a combat zone in sight of Viet
Cong patrols. A similar automatic switch was activated at Nha Trang on 3 June
1968. Subscriber message terminals to serve the U.S. forces were activated as
fast as the equipment was available. At the end of 1968, the Phu Lam switch
was serving twenty-eight subscriber terminals with an average daily

The 1st Signal Brigade was charged with the responsibility of operating and
maintaining not only the two automatic switching centers based in Vietnam, but
also all Army subscriber terminals that were connected to the big automatic
switches. The digital network provided the primary trunking for the Defense
Department's integrated automatic and nonautomatic message network in Vietnam.
At its peak, the system handled in excess of 100,000 messages per day, with
the Army portion of the network encompassing some eighty-six communications
centers with twenty-five automatic digital terminals. Within this count were
the automatic terminals provided to the combat divisions throughout the country.
From Camp Eagle in the north, near the city of Hue, home of the 101st Airborne
Division, to Cu Chi in III Corps Tactical Zone, home of the 25th Infantry Division,
communicators from the 1st Signal Brigade operated low-speed, 100-words-per-minute
automatic terminals. Usually mounted on vans but sometimes installed in a fixed
facility, these terminals provided the division commander with direct worldwide
access for message communications.

In only two years, from the activation of the Phu Lam automatic switching center
in 1968 to late 1970, the automatic message system in Vietnam expanded to meet
the requirements of centralized control and accurate, high-speed communications.
The impact of the Automatic Digital Network on record communications in a war
zone was immense because for the first time U.S. Forces possessed a reliable
and accurate high-speed method of ordering am­munition and repair parts, reporting
casualties, and requesting replacements.

In late 1969 some of the last necessary refinements were made on the message
communications system in Vietnam. The older manual message relay facilities
at Phu Lam and Da Nang were phased out of service. The Nha Trang relay had been
relegated to the less important role of minor relay in December 1968. These
re­lays had carried the burden of message communications in Vietnam and served
as the gateway stations to the rest of the world since the early 1960s. But
manual tape relays proved to be too slow for our modern army in combat. The
inevitable arrival of automatic switching in the combat zone marked the end
of an era in military communications, the end of the reliance on torn-tape relay
as the basis for message communications, and another step in our progress to
writer-to-reader secure communications.

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Tandem Switches-An Ultimate

At the end of 1968 the Southeast Asia Automatic Telephone Service was nearing
completion, and the many years of operator­assisted long-distance telephone
calls were coming to an end. In November of that year the first automatic long-distance
telephone switching center at Bang Pla, near Bangkok, Thailand, was completed
and cut over to service. The remaining switching centers in Vietnam and Thailand
were in various stages of completion. On 22 February 1969 the Can Tho automatic
switch was completed. Its cutover was followed by cutovers of centers at Korat,
Thailand, in :March, and at DA Nang in mid-April 1969. The telephone switching
centers at Tan Son Nhut and Nha Trang were completed at the end of July. Installation
continued at the centers of the remaining sites at Pleiku, Vung Chua Mountain
near Qui Nhon, and Ubon, Thailand. These last three switches became operational
by the end of 1969, thus completing the long-distance direct dial system for
Southeast Asia.

The nine switches comprising this system were connected to some fifty-four
automatic dial telephone exchanges of the Army, Navy, and Air Force in Vietnam
and Thailand, allowing selected subscribers and all dial telephone exchange
operators to dial directly any telephone subscriber in Southeast Asia, and giving
access into the worldwide Automatic Voice Network. The U.S. automatic dial telephone
exchanges in Vietnam, which had access to the long-distance system, were by
themselves processing over 1,000,000 telephone calls each day in 1969. (Map
8)

Another critical and essential long-distance telephone service was in the
area of command control. In the summer of 1967 the 1st Signal Brigade installed
small automatic telephone exchanges, dubbed "emergency action consoles,"
at the command operations centers of the U.S. Military Assistance Command in
Saigon and of U.S. Army, Vietnam, at Long Binh. These consoles provided automatic
telephone service to the essential subscribers in Saigon and Long Binh. In addition,
the control elements of the subordinate commands, down to separate brigade levels,
were connected to both emergency action consoles by separate long-distance telephone
circuits.

The Signal Soldier

The growth of U.S. and Free World Military Assistance Forces in the Republic
of Vietnam from 1962 to 1968 brought with it problems concerning the personnel
needed to operate and main-

[135]

MAP 8

tain the widespread communications facilities. The problems came from many
sources, among them the lack of certain select specialists and the introduction
of new equipment into Vietnam when the operators had no previous training in
the United States. Although

[136]

assigned strengths lagged behind authorized figures throughout the entire U.S.
Army in Vietnam, I will discuss here only those man­power problems that were peculiar
to the U.S. Army Signal Corps operating in Vietnam and the actions that were taken
to ease these problems.

Operation and maintenance difficulties often arose when new equipment was introduced
into Vietnam before the Army's schools in the United States could provide trained
men. This situation forced the operating signal units to take soldiers away
from their primary and essential duties and either give them on-the-job training
with the new equipment or send them to the 1st Signal Brigade's Army Training
Facility at Long Binh for formal instruction. Typical examples of such equipment
were the commercial dial switching gear of the telephone network and the data
transmission terminals associated with the Automatic Digital Network.

One of the most critical manpower shortages was in the specialty of communications
cable-splicer. Long before the communications expansion in Vietnam, the decision
had been made by the U.S. Army to discontinue cable-splicing as a course of
instruction and instead to send Army students to the joint course conducted
by the Air Force at Sheppard Air Force Base in Texas. As heavy cable construction
became routine in all of the large Vietnam base camps, it was apparent that
the numbers graduating from this joint course could not meet the requirements
of the U.S. Army, Vietnam, for trained splicers. The shortage was largely alleviated
by introducing a cable-splicing course at the 1st Signal Brigade's Army Training
Facility in Vietnam. While this method produced a journeyman-soldier capable
of beginning work on heavy cable construction projects and making repairs, the
time he spent at the school decreased the time left in the soldier's 12-month
tour in which his new-found skills could be put to use. We also had difficulties
in other fields. Many microwave, tropospheric scatter, radar, computer, and
cryptographic specialists arriving in Vietnam needed additional training before
they could perform their tasks in an acceptable manner. These men were given
refresher courses at the brigade's training facility.

Another area of concern was that signal personnel arrived in Vietnam from two
different sources. Signal officers and men for the 1st Signal Brigade were requisitioned
through channels of the Strategic Communications Command from the Department
of the Army. Men for the signal units of the field forces, divisions, and

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CABLE-SPLICERS AT WORK AT A LARGE FIXED BASE

separate brigades were requisitioned through U.S. Army, Vietnam, from the Department
of the Army. Of necessity, requisitions were submitted many months in advance
of the arrival of the replacements, and often the requirement for an individual
with a particular specialty in a specific unit had been satisfied by other means
prior to his arrival in Vietnam. In order to utilize replacements most effectively
and retain the flexibility necessary to respond to the changing requirements,
a weekly meeting was established in 1968 between the 1st Signal Brigade and
the communications-electronics staff of the U.S. Army, Vietnam, to discuss the
personnel situation. Decisions were then made to divert incoming manpower resources
or to reassign men already in Vietnam to meet urgent requirements. Through this
procedure the possible detriment of the dual replacement stream was avoided,
and an effective method emerged for using signal officers and enlisted men arriving
in Vietnam.

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Supply and Maintenance Support

The communications equipment used in Vietnam ranged in size and complexity
from large, fixed-plant items to the squad radio used by the infantry soldier.
All this equipment required an efficient repair and supply system in order to
insure continuing communications. The procedures for providing this support
differed between the mobile and fixed communications items and these differences
ultimately led to problems.

An appreciation of the difficulties inherent in communications supply support
can be gained by an examination of the sheer magnitude of the communications-electronics
logistics effort at the height of the Vietnam War. An estimated one-third of
all the major items of equipment in Vietnam were communications-electronics
items. Over 50,000 different types of communications-electronics replacement
and repair parts were stocked by the supply system in Vietnam. And there were
more than 150 direct and general support supply and maintenance facilities in
Vietnam that dealt with communications-electronics equipment.

The supply and maintenance support for the communications equipment of the
combat units and of the corps area support battalions under the 1st Signal Brigade
was standardized, following the guidelines of the Army's logistics doctrine.
This support functioned as effectively as the over-all Army logistics system
in Vietnam functioned. When the U.S. Forces began to arrive in strength, the
huge logistical buildup created unprecedented problems which the Army had to
solve in order to fight a computerized war in the counterinsurgency combat environment
of Vietnam. However, in time the depot and support command system of management
functioned well, and the computer as a tool of logistic management came of age
in Vietnam.

The standardization that was possible for mobile communications-electronics
equipment was not feasible for the fixed-plant communications equipment used
in Vietnam. Our fixed signal equipment in Southeast Asia was mainly a combination
of commercial equipment provided by and partly or wholly maintained by two commercial
contractors. Such equipment was new to the Army and involved uncommon components
that were not found at all in the field army maintenance support system. These
items, therefore, presented unprecedented problems for the logistician in the
matter of the availability of repair parts, the application of standard Army
maintenance doctrine, and the training of military technicians to maintain the
equipment.

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CALIBRATING EQUIPMENT AT 1ST SIGNAL BRIGADE CAN THO SITE

The problems were apparent to both the logistician and the communicator alike.
During the summer of 1968 a Department of the Army team, headed by Brigadier
General Hugh F. Foster, Jr., prepared a study of communications-electronics
support in Southeast Asia. The study defined the logistics concepts and the
support responsibilities for the fixed communications systems in Southeast Asia.
Specifically, it recommended that three area maintenance and supply facilities
be established, two in Vietnam and one in Thai­land. These facilities, to be
operated solely by and for the 1st Signal Brigade, were to furnish the maintenance
and supply support for the commercially procured, fixed-plant communications
equipment in Southeast Asia.

In October 1968 approval of the recommendation came from the Department of
the Army, and construction of facilities at Bangkok, Thailand, and at Long Binh,
Vietnam, was begun promptly. The Thailand complex, under the 29th Signal Group,
became operational in June 1969, and the Long Binh facility followed a month
later. Shortly thereafter, construction was started

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on the third facility at Cam Ranh Bay, which became operational in the spring
of 1970.

The activation of these area maintenance and supply facilities solved one
of the major problems in the support of fixed communications systems. These
systems, previously supported by contracts and ill-defined maintenance and supply
channels, were now supported from a single central facility in each of the three
designated geographical areas of responsibility.